ABSTRACT The goal of this proposal is to investigate how the brain encodes tactile motion information in the brain. Responses within different areas of primary somatosensory cortex (SI) will be examined (areas 3a, 3b, 1, and 2). Central to understanding their functional roles is finding out what distinguishes one area from another. By using simple versus complex stimuli, we aim to distinguish between areas whose responses are closely associated with the physical nature of the stimulus and areas whose responses are invariant and more closely reflect the motion percept. We will employ optical imaging, voltage sensitive dye imaging, BOLD fMRI, single unit recording, and anatomical tracing methods to address these questions. These experiments will elucidate the neural circuitries underlying tactile behavior and attention, understanding that will have clinical relevance for recovery of function from stroke and development of tactile prosthetics. 2